(1) Field of the Invention
The present invention relates to a novel laminate.
(2) Description of the Related Art
In the packaging of certain products, such as food products in particular, it is highly desirable to impede or prevent the transmission of oxygen and/or water vapor through the packaging. While the permeation of oxygen or water vapor itself is not necessarily harmful to the product, the quality and shelf-life of the product may deteriorate when exposed to these elements.
In packaging containers of varying shapes and constructions, 100% aluminum seals are often used to protect the products inside the container from oxygen or water vapor. These seals are often bonded between the container itself and some type of lid. In other configurations, the aluminum seal may be the only lid that the container has.
Seals made from aluminum are often selected based on the superior barrier properties of aluminum. The effectiveness of such barriers depends on both the type of material employed and the barrier's thickness. For example, a 0.001 inch layer of 100% aluminum foil is impermeable to moisture and oxygen and a 0.00035 inch layer of 100% aluminum foil has a water vapor transmission rate of 0.02 grams or less per 100 square inches.
Due to the ever-increasing cost of aluminum, however, it has become necessary to find alternative membranes which are less expensive than aluminum yet still deliver the necessary barrier properties. In addition, high gauges of aluminum used in known membranes also pose some risk to consumers if the consumer punctures the seal by hand. Specifically, the sharp aluminum edges surrounding the puncture location can cause minor scratches or cuts to the hand. Attempts to substitute more cost effective substitutes for the 100% aluminum seals have been met with limited success. One reason is because in addition to the necessary barrier properties, the replacement material must also be able to withstand various manufacturing and processing conditions to which the packaging containers are subjected.